Aqueous stream purifier and method of use

Abstract

An electrolytic method is provided for purifying an aqueous stream, including at least one contaminant ion. In one embodiment, the eluent stream flows through a purifying flow channel, including ion exchange bed, an electric field is applied through the flowing eluent stream in the purifying flow channel, and the contaminant ion is removed from the eluent stream. In another embodiment, no electric field is applied and the ion exchange bed is periodically regenerated. Two beds may be used with one bed on line while the other bed is regenerated followed by a reversal of flow.

1. A method for electrolytically purifying an aqueous stream, adding a liquid sample stream containing an analyte ion to said purified aqueous stream, and detecting said analyte ion, said aqueous stream including at least one contaminant ion, said method comprising
 (a) flowing said aqueous stream through a purifying flow channel having an inlet and an outlet, 
 (b) applying an electric field through said flowing aqueous stream in said purifying flow channel between first and second spaced electrodes of opposite charge, said first electrode being of opposite charge to said contaminant ion, and 
 (c) removing said contaminant ion, but not ions of opposite charge to said contaminant ion, from said aqueous stream in said purifying flow channel to produce a purified aqueous stream which flows out said flow channel outlet while drawing said contaminant ion toward said first electrode, 
 (d) adding a liquid sample to said purified aqueous stream exiting from said purifying flow channel, said liquid sample comprising at least a first analyte ion, said analyte ion being of the same charge, positive or negative, as said contaminant ion, and 
 (e) detecting said analyte ion. 
 
     
     
       2. The method of  claim 1  in which said aqueous stream comprises an eluent comprising and electrolyte comprising selected ions of one charge, positive or negative, said contaminant ion being of opposite charge to said selected ions. 
     
     
       3. The method of  claim 1  in which flow-through ion exchange medium having exchangeable ions of the same charge as said contaminant ion is disposed in said purifying flow channel. 
     
     
       4. The method of  claims 1  or  3  in which said second electrode is disposed proximal to said purifying flow channel outlet. 
     
     
       5. The method of  claim 1  in which said first electrode is separated from said purifying flow channel by a barrier which permits the flow only of ions of the same charge as said contaminant ions. 
     
     
       6. The method of  claim 5  in which said barrier blocks substantial bulk liquid flow. 
     
     
       7. The method of  claim 5  in which said barrier is disposed along the purifying flow channel in contact with the eluent stream therein. 
     
     
       8. The method of  claim 7  in which said barrier is disposed between said purifying flow channel inlet and outlet. 
     
     
       9. The method of  claims 1  or  5  in which said first electrode is disposed in a first electrode chamber, said method further comprising flowing an aqueous solution through said electrode chamber to remove contaminants therefrom. 
     
     
       10. The method of  claims 1  or  5  in which said first and second electrodes are disposed generally parallel to said purifying flow channel. 
     
     
       11. The method of  claim 1  in which said first electrode is disposed proximate to said purifying flow channel inlet and said second electrode is disposed proximal to said purifying flow channel outlet. 
     
     
       12. The method of  claim 1  in which said contaminant ion is carbonate or bicarbonate ion. 
     
     
       13. The method of  claim 1  in which said liquid sample includes at least a second analyte ion, said method further comprising
 (f) separating said first and second analyte ions of interest prior to detecting in step (e). 
 
     
     
       14. The method of  claim 13  in which said separating is performed by chromatography. 
     
     
       15. A method for electrically purifying an aqueous stream, adding a liquid sample stream containing an analyte ion to said purified aqueous stream, said aqueous stream comprising an acid including an acid anion or a base including a base cation, said aqueous stream further including at least one contaminant ion of opposite charge to said acid anion for said acid aqueous stream and to said base cation for said base aqueous stream, said method comprising
 (a) flowing said acid or base aqueous stream through a purifying flow channel having an inlet and an outlet, 
 (b) applying an electric field through said flowing aqueous stream in said purifying flow channel between first and second spaced electrodes of opposite charge, said first electrode being of opposite charge to said contaminant ion, 
 (c) removing said contaminant ion but not said acid anion or base cation from said aqueous stream in said purifying flow channel to produce a purified acid or base aqueous stream which flows out said flow channel outlet while drawing said contaminant ion toward said first electrode 
 (d) adding at least a first analyte ion to said purified acid or base aqueous stream exiting from said purifying flow channel, said first analyte ion being of the same charge, positive or negative, as said contaminant ion. 
 
     
     
       16. The method of  claim 15  further comprising the steps of:
 (e) flowing effluent from said chromatography medium through a suppressor chromatographic effluent flow channel separated by an ion exchange membrane from a suppressor regenerant flow channel, and 
 (f) flowing an aqueous liquid from said regenerant flow channel past said first electrode and removing aqueous solution in contact therewith. 
 
     
     
       17. The method of  claim 15  in which said liquid sample comprises at least a second analyte ion, said method further comprising
 (e) after step (c), separating said first and second analyte ions, and 
 (f) detecting said separated analyte ions. 
 
     
     
       18. The method of  claim 17  in which said separation is performed by chromatography in a chromatography medium having the same charge, positive or negative, as said contaminant ion. 
     
     
       19. The method of  claim 18  further comprising the steps of:
 (g) flowing effluent from said chromatography medium through a suppressor chromatographic effluent flow channel separated by an ion exchange membrane from a suppressor regenerant flow channel, and 
 (h) flowing an aqueous liquid from said regenerant flow channel past said first electrode and removing aqueous solution in contact therewith. 
 
     
     
       20. The method of  claim 15  in which said first electrode is separated from said purifying flow channel by a barrier which permits the flow only of ions of the same charge as said contaminant ions. 
     
     
       21. The method of  claim 20  in which said first electrode is disposed in a first electrode chamber, said method further comprising flowing an aqueous solution through said electrode chamber to remove contaminants therefrom.